Solving Systems Using Substitution and Elimination

What is the best method to use?

−4x − 2y = −12

4x + 8y = −24

• Substitution

• Elimination

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Erin is 3 years younger than twice Alex's age. Their ages combined are 33 years. How old are Alex and Erin. If x=Erin's age and y=Alex's age, choose the system that matches the situation.

• x + y = 33
  y = 2x - 3

• x + y = 33
  x = 2y - 3

• x + y = 33
  x = 3 - 2y

• x + y = 3
  x = 33 - 2y

Tags

CCSS.HSA.CED.A.3

What does the second equation need to be multiplied by to get the y's to eliminate?

• 5

• 0

• -1

• 2

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

• (0, -4)

• (2, 4)

• No solution 

• (2, 0)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve by elimination:
4x+4y=4

3x+4y=10

• (7,-6)

• (-6,7)

• (6,7)

• (7,6)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

y = -6x + 5
-2x + y = 5

• (-3, -6)

• (-6, 3)

• (0, 5)

• (-3, 5)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

3x + y = 1
y = 4x + 1

• (0, -1)

• No Solution

• (0, 8)

• (0, 1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

x + 2y = 2
x = -4y + 2

• (-3, 0)

• (0, 2)

• (-3, -2)

• (2, 0)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

x - 3y = -13
4x + 2y = 4

• (1, 4)

• (-1, -4)

• (-1, 4)

• (1, -4)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6

Solve for x and y
y = 2x + 1
y = 4x - 1

• (1,3)

• (-1,-3)

• (-1,3)

• (3,1)

Tags

CCSS.8.EE.C.8B

CCSS.HSA.REI.C.6